Thousands of festival fans missed the events because of the scams
Music festival fans have being warned to be extra vigilant when buying tickets online after thousands were left out-of-pocket and ticketless.
Detectives from the Serious Fraud Office are now investigating after an estimated £1m worth of tickets failed to be delivered to fans.
Those expecting to attend the Leeds and Reading festivals suffered a "monstrous crime" said festival chief Melvyn Benn.
Fans were advised to use the official website or authorised ticket agencies.
Mr Been said his team had been left to deal with disappointed fans who not only missed their music weekend but had also lost a lot of money through the scams.
Around 80,000 fans attend the Leeds festival at Bramham Park.
But last year an estimated 2,000 people failed to gain access to the site because they did not have the tickets they had paid for.
Mr Benn said: "It's an absolutely monstrous crime, and I would say that between the Leeds and Reading festivals £1m was taken on scams.
"It's shocking, people then begin to lose faith in my industry.
"It's massively disappointing because it's me and my team that have to deal with them and say 'not only can you not come in, but they've got your money as well'."
The organisers said some festival fans may not even realise they have been fleeced until they turn up on the day of the festival and find they have no right of entry to the site.
Fans warned of ticket scams